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Almonds in the diet simultaneously improve plasma α-tocopherol concentrations and reduce plasma lipids

https://doi.org/10.1016/j.jada.2004.12.002Get rights and content

Abstract

The objective of this study was to assess the dose-response effect of almond intake on plasma and red blood cell tocopherol concentrations in healthy adults enrolled in a randomized, crossover feeding trial. Participants were 16 healthy men and women, aged 41±13 years. After a 2-week run-in period, participants were fed three diets for 4 weeks each: a control diet, a low-almond diet, and a high-almond diet, in which almonds contributed 0%, 10%, and 20% of total energy, respectively. Changes in blood tocopherol levels were assayed by high pressure liquid chromatography. Incorporating almonds into the diet helped meet the revised Recommended Dietary Allowance of 15 mg/day α-tocopherol and increased lipid-adjusted plasma and red blood cell α-tocopherol concentrations. A significant dose-response effect was observed between percent energy in the diet from almonds and plasma ratio of α-tocopherol to total cholesterol.

Section snippets

Methods

Sixteen subjects were selected from those participating in a randomized feeding trial investigating lipid responses to graded almond intakes (8). Those selected were male (n=8) and female (n=8) participants not taking multivitamins, vitamin E, or other dietary supplements before and during the study. Pertinent characteristics were age (41±13 years), body weight (71±2.7 kg), and body mass index (calculated as kg/m2) 25.2±3.6. The Institutional Review Board of Loma Linda University approved the

Results

Our study demonstrates that incorporation of almonds into the diet both increases blood α-tocopherol levels and decreases cholesterol levels. Table 1 shows plasma, RBC tocopherols, and serum lipids at the end of each dietary treatment. Compared with the control diet, plasma α-tocopherol concentrations increased significantly on the low- and high-almond diets. Mean plasma γ- and β-tocopherol concentrations decreased with the low- and high-almond diets in both plasma and RBCs. The ratio of

Discussion

According to current recommendations (3), the only physiologically pertinent form of vitamin E is α-tocopherol. Although all vitamin E forms are absorbed and transported by chylomicrons from the intestine to the liver, the liver preferentially secretes α-tocopherol into the circulation. This is regulated by the hepatic α-tocopherol transfer protein (11, 12). Consequently, although γ-tocopherol accounts for as much as 70% of total intake of tocopherols in the United States, plasma α-tocopherol

Conclusions

  • The recommended dietary allowance for vitamin E has been increased to 15 mg/day α-tocopherol for both men and women. The typical US diet is low in α-tocopherol. One ounce of almonds (165 kcal) can be isocalorically substituted for white bread, crackers, chips, and similar refined products to provide 7.4 mg α-tocopherol.

  • Other than almonds, foods that provide >4 mg α-tocopherol in a typical serving are sunflower seeds, hazelnuts, wheat germ, wheat germ oil, sunflower oil, cottonseed oil, and

P. R. Jambazian is associate professor, School of Kinesiology and Nutritional Science, California State University, Los Angeles.

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    P. R. Jambazian is associate professor, School of Kinesiology and Nutritional Science, California State University, Los Angeles.

    E. Haddad is associate professor, S. Rajaram is assistant professor, and J. Sabaté is chair and professor, all with the Department of Nutrition, School of Public Health, Loma Linda University, Loma Linda, CA.

    J. Tanzman is with the School of Public Health, Loma Linda University, Loma Linda, CA.

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